A channel state information-reference signal (CSI-RS) is used as a reference signal for channel state information measurement in a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system. To further improve spectrum efficiency, more antenna configurations, especially antenna configurations of more than eight antenna ports based on an active antenna system (AAS), are introduced in a current LTE R13 standard. For example, there may be 16, 32, or 64 antenna ports.
In a current technology, both a CSI reporting type A and a CSI reporting type B are supported. CSI measurement in the CSI reporting type A is based on a non-beamforming CSI-RS resource, and CSI measurement in the CSI reporting type B is based on a beamforming CSI-RS resource. A CSI process corresponding to the non-beamforming CSI-RS resource is a CSI process of the type A, and a CSI process corresponding to the beamforming CSI-RS resource is a CSI process of the type B. As a quantity of antenna ports increases, reference signal resource overheads in the CSI process of the type A accordingly increase.